... 4+4cm, surface polished, with anti slip, Black Granite Stair SpecificationStone step 2cm and 3cm, double step 3+3cmFinishPolished,Flamed ... ,Honed,Bushhammered,Sandblasted,Brushed,etc.Avaliable colorsGranite and Marble from China,India,Brazil,Norway,South Afraca, ... customer.Ordinary do 3+3cm thickness double step.The fiber and glue are from Germany.Advantage1) More than 15 years ...